87 Effect of Body Warming on Blood Flow Distribution in Hypoxic Infant Rabbits
Bibliographic record
Abstract
Newborn and small mammals, including human infants, respond to acute hypoxia (Hx) with a drop in body temperature (Tb). Yet, normal clinical practise is to maintain Tb within the normal range which may involve body warming. Previous experiments showed that warming hypoxic newborns reduced peripheral vascular resistance and increased cardiac output, suggesting that the normal redistribution of blood flow (BF) in Hx to the vital organs may be compromised. To evaluate the effect of body warming in hypoxia on the distribution of BF to specific organs. The fluorescent microspheres technique was used to compare the BF distribution in young rabbits (1 month age) during Hx (FIO2=10%) with (n=9) and without (n=10) body warming. BF was measured in brain, GI tract, hindlimb muscle, diaphragm, skin, and kidneys, in normoxia (Nx) at 15°C ambient temperature (Ta), after 60 min of Hx at Ta = 15 °C, and again after a further 60 min of Hx at Ta =15°C or 27°C. A Ta of 27°C was sufficient to increase Tb to the Nx value in 40 min. Mean arterial blood pressure, oxygen consumption, hemoglobin O2 saturation and blood gases were also measured. Statistical analysis was performed using a mixed factorial two-way ANOVA. In Hx all animals dropped Tb (−1.8°C), and BF significantly increased to the brain (+50%), diaphragm (+76%) and hindlimb muscle (+28%), decreased to the GI tract (stomach: −25%, small intestine: −30%), and was unchanged in the remaining organs; these changes with Hx are similar to those reported by others. The increase in brain BF was sufficient to maintain O2 supply at the Nx level. Re-warming significantly changed the hypoxic pattern of BF. Brain BF further increased by 100%, thereby elevating O2 supply to a level 50% above the Nx value. BFincreased to the skin (+55%), and GI tract, however these increases were insufficient to return O2 supply to the Nx level. BF decreased to hindlimb muscle and diaphragm; BF to the former decreased below even the Nx level (−30%), whereas BF to the diaphragm was still above the Nx value (+11%). Warming alters the pattern of hypoxic BF redistribution such that BF is increased to the periphery. However, this increase did not come at the expense of brain BF. However, warming did not provide any great improvement in O2 delivery. We conclude that warming may simply impose an additional demand on the cardiovascular system.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.001 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".